This product includes cryptographic software written by Eric Young (eay@cryptsoft.com).

This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit (http://www.openssl.org/).

This page provides the documentation of the HALCON OPC Classic interface. Only interface-specific parameters and features are described here. For general information of the operators for I/O interfaces please have a look at the HALCON Operator Reference.
Registered customers can download the latest revision of this interface from the MVTec WWW server.

• Intel compatible PC with Windows Vista/7/8, Windows Vista/7/8 x64, also WoW64 (using 32-bit HALCON on 64-bit Windows).
• OPC Core Components Redistributable package for Windows x86 or Windows x64. If this package is not installed, please download and install it from the OPC Foundation website.
• Windows: HALCON I/O device interface hioOPC_Classic.dll or hioOPC_Classicxl.dll, respectively. Also required are libeay32.dll, ssleay32.dll, and uastack.dll. If you have properly installed the interface, all these DLLs should reside in bin\%HALCONARCH% within the HALCON base directory %HALCONROOT% you have chosen during the installation of HALCON. Please note that the HALCON OPC_UA interface uses the same DLLs.

Only when installing or updating the interface manually follow these steps:

• Windows: Extract the archive containing the interface files to the HALCON base directory %HALCONROOT% (Note: Administrator privileges may be required for this step). Additionally, you have to move the interface examples to the directory %HALCONEXAMPLES% manually.
• Linux: Extract the archive containing the interface files to the HALCON base directory $HALCONROOT.

• Implementation of an OPC Classic (also known as OPC DA, OPC ComDA) client.

• Only OPC Data Access (OPC DA) is supported.
• No OPC device discovery. OPC Classic server name must be set according to the setup of the server.
• No support for public groups.
• The OPC Classic I/O interface returns and expects all strings in UTF-8 encoding.
• All dates and times are assumed to be UTC.
• The OPC Classic I/O interface only supports one-dimensional arrays, and it can only do so if a single OPC value is being read or written (i.e., if read_io_channel or write_io_channel are used with multiple channel handles, only scalar values are allowed in each channel).
• On 32-bit systems, 64-bit OPC integer values (both signed and unsigned) cannot be properly represented. They can only be used if the actual value fits within a 32-bit integer.

The open_io_device operator is used to connect to an OPC Classic server. Specify the URL of the server to connect to with the IODeviceName parameter. The server URL is generally in the form 'opcda://<machine name>/<server ProgID>[/<CLSID>]'.

OPC Classic has a rich set of data types that have to be mapped to the HALCON control tuple data types integer, real and string on input and output. The HALCON OPC Classic I/O device interface supports the following built-in OPC data types:

• Boolean
  A boolean value, translated to and from the HALCON strings 'true' and 'false'.
• SByte, Int16, Int32, and Int64
  These types are translated to and from HALCON integer values. On 32-bit systems, 64-bit integers outside the range of a 32-bit integer cannot be represented.
• Byte, UInt16, UInt32, and UInt64
  These types are translated to and from HALCON signed integer values. An unsigned value outside the range of HALCON's signed integers is represented as the signed integer corresponding to the bit pattern of the unsigned integer. On 32-bit systems, 64-bit integers outside the range of a 32-bit integer cannot be represented.
• DateTime
  The date is translated to and from the number of seconds since January 1, 1970 as a HALCON real value.
• Double and Float
  These types are translated to and from HALCON real values.
• String
  This type is represented as a HALCON string. Please note that the OPC Classic I/O interface returns and expects all strings in UTF-8 encoding.

OPC Classic items are referenced by using their item ID written as a string as the channel parameter in the query_io_device and open_io_channel operators.

There may exist additional parameter attributes, which can be accessed as 'ParamNames.AttributeName'. The following standard attributes may be available:

• '.access': This attribute provides the access permissions of the corresponding parameter as a string. Possible values are 'ro' (read-only), 'wo' (write-only), 'rw' (read/write), 'na' (unavailable, perhaps due to insufficient access rights), and 'ni' (unavailable, not defined for this device or channel).
• '.category': This attribute provides the category of the corresponding parameter as a string. 'I/O interface' for all pre-defined I/O interface parameters.
• '.default': This attribute provides the default value of the corresponding parameter.
• '.description': This attribute provides the description of the corresponding parameter as a string.
• '.displayname': This attribute provides the displayname of the corresponding parameter as a string.
• '.range': This attribute provides the minimum and maximum, (and the step width, if applicable) for the corresponding integer or float parameter as a tuple with 2 (or 3) elements.
• '.representation': This attribute provides how the value of the parameter should be displayed in a GUI: 'ip address', 'hex', ...
• '.tooltip': This attribute provides the tool-tip of the corresponding parameter as a string.
• '.type': This attribute provides the HALCON value type (integer, real, or string) of the corresponding parameter as a string.
• '.values': This attribute provides the valid value list for the corresponding parameter as a tuple.
• '.visibility': This attribute provides the visibility of the corresponding parameter as a string. Possible values are 'common', 'extended', and 'dangerous'.
• '.unit': This attribute provides the units of the corresponding parameter as a string. For example: 'ns', 'us' and 'ms', or 'mm', 'cm', 'dm' and 'm'.

There may exist additional parameter attributes, which can be accessed as 'ParamNames.AttributeName'. The following standard attributes may be available:

• '.access': This attribute provides the access permissions of the corresponding parameter as a string. Possible values are 'ro' (read-only), 'wo' (write-only), 'rw' (read/write), 'na' (unavailable, perhaps due to insufficient access rights), and 'ni' (unavailable, not defined for this device or channel).
• '.category': This attribute provides the category of the corresponding parameter as a string. 'I/O interface' for all pre-defined I/O interface parameters.
• '.default': This attribute provides the default value of the corresponding parameter.
• '.description': This attribute provides the description of the corresponding parameter as a string.
• '.displayname': This attribute provides the displayname of the corresponding parameter as a string.
• '.range': This attribute provides the minimum and maximum, (and the step width, if applicable) for the corresponding integer or float parameter as a tuple with 2 (or 3) elements.
• '.representation': This attribute provides how the value of the parameter should be displayed in a GUI: 'ip address', 'hex', ...
• '.tooltip': This attribute provides the tool-tip of the corresponding parameter as a string.
• '.type': This attribute provides the HALCON value type (integer, real, or string) of the corresponding parameter as a string.
• '.values': This attribute provides the valid value list for the corresponding parameter as a tuple.
• '.visibility': This attribute provides the visibility of the corresponding parameter as a string. Possible values are 'common', 'extended', and 'dangerous'.
• '.unit': This attribute provides the units of the corresponding parameter as a string. For example: 'ns', 'us' and 'ms', or 'mm', 'cm', 'dm' and 'm'.

Operator write_io_channel